Aneuploidy is associated with premature aging in humans, but it is not possible to distinguish whether this is caused by the imbalance of some gene products or by the cumulative imbalance of many loci. Segmental aneuploidy in Drosophila is a means of creating zygotes which are unbalanced at a given chromosomal region. Hence specific loci can be mapped on the basis of their aneuploid effect to cause premature aging. This will be carried out for the X chromosome by means of X;Y translocations to create appropriate duplication on deficiency-bearing flies. Specific regions identified will be subjected to mutational analysis of their gene content and to directed selection for longevity variants. The correlation between the aneuploidy effects on viability (development) and longevity will also be probed in this way. Additional studies are proposed to further the aneuploidy phenotypes associated with specific chromosome regions.